Pneumatically-actuated machine gun



Jan. 14, 1930. R. B. SMITH 1,743,576

PNEUMATICALLY ACTUATED MACHINE GUN v Filed July 14. 1927 ATTORNEY Patentedl Jan. 14, 1930 UNITED STATES ROBERT :BTGHAM sm'rTn', 'or ATLANTA, GEORGIA PNEUMATICALL/'LY-ACTUATED MACHINE GUN Application led July 14, 1927. Serial lN'o. 205,832.

The invention relates in general to a machine gun of the pneumatically actuated type, and the invention specifically relates to such a form of gun particularly designed as a military training device and as an amusement pirla-(vice for use in shooting galleries land the It has been known to feed projectiles, sometimes in the form of spherical balls, to the gun barrel and project the same by means of air or gas under pressure sometimes by means of,an air pump but more often by means of an exploded charge of gas. These known devices have the disadvantage in that the gases so discharged are obnoxious especially in close quarters and otherwise such devices are not designed for indoor use. Such Cdoevices which depend upon an air pump for supplying the projectile propelling air are not par- `ticularly designed nor'adapted for economic operation should an attempt be made to utilize them as amusement devices or in a shooting gallery. Should the smallv air pump of the known art be enlarged to-generate air under. compression as would discharge the projectile for any material distance, the size ofsuch an air pump and the cost of operating it would be prohibitive as a shooting gallery equipment.

Accordingly, the primary object of the invention is to provide an extremely simplified form of pneumatically -actuated gun and actuating mechanism which can be marketed as a complete, compact and inexpensive unit and' installed for` use within doors; which can be operated economically and continuously and which will simulate the action ofa rapid fire machine gun of conventional form.

Broadly, this invention is attained by providing a condenser of relatively small volumetric capacity and a motor for driving the same forming an air pressure generator-f capable of instantly generating sufficient pressure to discharge the projectiles to the requisite distance. The compressor is in direct fluid connection with the gun barrel and interposing therebetween is a normally closed spring resisted valve which will permit the accumulation of pressure in rearofthe same and delayf` the -discharge until suchA pressure has reached a pre-determined point at which it is automatically released into the gun lbarrel to act on the projectiletherein.

Another object of the invention and also featuring economy in operation is to .provide a form of control to simulate the usual trigger operation so that pressure on the ,trigger finger will cause the compressor to function and the gun to discharge simulating the action of conventional forms of guns.

Still another object of the invention is to provide a projectile feeding magazine which will insure a constant feeding of the projectiles to the gun barrel irrespective of the rate at which they are discharged from the barrel.

' Broadly, this phase of the invention is attained by agitating the projectiles in the magazine during the time the gun is in operation and preferably by controlling the agitation by the tiring control, in this instant by v actuating the trigger, which also controls the functioning of the air compressor.

Various other objects and advantages of the invention will be in part obvious from an inspection of the accompanying drawings and in part will be more 'fully set forth in the following particular description of one 'form of mechanism embodying'my invention,

and the invention also consists in certain new and novel features of constructlon and combination of parts hereinafter set forth invention; y

Fig. 2 is an enlarged detail view taken'in vertical section showing the receiving or breach endof the gun barrel and the associated trigger control `for the compressor an agitator; and Fig. 3 is a horizontal sectional view of the magazine and agitator taken on the line 3 3 of Fig. 1. v It is understood that the construction as shown in Fig. 1 is intended to be a complete marketable unit designed to be installed in position with a part extending below a counter @with the bottom'of the unitpresting on a support 10 and with the gun proper 11 extending above the counter 9. The unit includes a mechanism containing casing 12 with its upper` portion reduced to '-form an upstandin socket 13 designed to receive one element o a swivel joint 14 formin art of the replaceable gun. Contained Wit in the casin 12 is a relatively small air compressor 15 o the reciprocating single piston type operatively connected to be driven conventionally from a small electric motor 16. To the upper, discharge end 17 of the compressor extends a flexible tubing 18 intruded through an opening 19 in the casing 12 and leading to the gun which is pivotally mounted by means of swivel joint 14 so as to permit universal aiming of the gun as is usual in such constructions. The gun is designed to simulate a conventional form of machine gun and includes stock 20, handle 21, trigger 22, sight 23 and other usual parts. The gun barre 24 is provided adjacent its rear or stock end with a projectile feeding conduit 25 opening through the top of the casing and ada ted to receive projectiles 26 fed thereto onelby one from the magazine 27 hereinafter more fully described. The rear end of the un barrel is defined beyond lthe conduit 25 y an L-shaped air conduit 28, the lower end of which is formed into a nipple 29 projecting downwardl through the casin and to which is afixe the u per, free en of the conduit 18, demountab y secured in position by a strap 30. The upstanding portion 31 of the conduit 28 has its bore constricted to provide a valve seat 32 on which is normally seated a.spherically shaped valve 33 maintained on its seat by a compression spring 34. The upper or opposite end of the spring 34 is set in adjustable position by means of a sto 35 in turn adjusted by a set screw 36 whic is threaded through a nut 37 screwed into the vupper end of the arm 31 and rotated by means of a knurled head 38.

From this construction it is seen that the valve 33 will be held in s ring pressed engagement with its seat until the air ressure in the conduit 18 is sufiicient to move t e valve o its s'eat into open position and' thus perit the accumulated charge of compressed air to act upon the projectile which is in position in the gun barrel as shown in Fig. 2 to discharge the projectile from the gun barrel.

The magazine 27 is in the form of a cylindrical drum sup rted from the gun 11 by means of brac ets 40 so as to move with the "un and maintain a projectile chute or con uit 41 in communication with the conduit 25 so as to supply rojectiles in a continuous stream and one a ter the othery to thegun barrel. The projectiles may be ermitted to flow conventionally to the gun arrel by gravity but Where the gun is intended to discharge the projectiles in rapid sequence it is Lnasvo suggested `that some suitable means be positioned in the magazine in order to maintain the mass of rojectiles or at least the layerstanding centrally positioned driving shaft 46 journalled in the partition and `vto the lower end of which is secured a hub 47 and agitating blades 48 extend regularly from the hub. As these blades rotates under the turning action of the shaft, they will tend to sweep the projectiles across and into the intake end of the conduit 41. Positioned in Athe compartment 44 is an agitator motor 50 connected by a gear drive 51 with the shaft 46.

1t is intended that the device thus disclosed is to be connected to an electric light circuit or other suitaible force of electric energy for driving the motors 16 and 50 and so that the opening and closing of .the circuit may be governed by the trigger action of the gun. For this purpose the motors 16 and 50 are connected in parallel and controlled by a `circuit closer 51. The movable element 52 of the circuit closer'forms a continuation of the trigger finger 22 of the gun as particularly shown in Fig. 2. The movable element 52 is normally maintained in circuit open position by means of a retractile spring 53.

Describing the electric wiring it is noted that a main lead 54 from the socket or other source of current leads to the motor 16, from the motor 16 conductor 55 leads to the movable element of the circuit closer 51. Conductor 56 leads from the fixed element 52 of the circuit closer and constitutes the return to the main line 57. Shunt leads 58 and 59 of the upward or compression stroke of the compressor the pressure is not intended to be suicient to overcome the closing'resistancemlgo,V ofthe sprin 34. The tension of this Spring has previous y been adj usted so ,that the valve will open, preferably at the instantmaximum pressure is attained in the conduit 18. It is obviously possible, however, by adjusting the screw 36 to regulate the opening movement of xthe valve even to the extent of requiring several strokes of the compressor plstnn to accumulate the required pressure to open the valve. In this case, of course, the compressor pressor and the agitator. At the beginning would have to be provided with a conventional form of non-return .valve at its outlet,

L but the preferable structure is to provide an extremely sim lifle'd and thus cheap form of compressor without valves and to have a direct fluid connection between the compressor and gun and thus eliminate any necessity of a reservoir of compressed air usually used in such constructions. f

By meansof the device of the class disclosed, there has been avoided any necessity of providing air ressure tanks and the sealing means for de eating leaka e in such'tanks and connections therewith. he ressure is not generated until about to be A con# tinual supply of projectile ejecting air is being generated only while'the gun is 1n active operation and the generation ofI compressed air is interrupted automatically and prompt? ly simply by releasing the trigger. It this interruption of air pressure generation which causes the cessation of the tiring operation. The entire operation is auto `atic. It is simply requiredoff'the operator ,Y at he ress.

on the triggeringer as 1s usual in the rm of machine guns and the firing operation wi continue as lon as there are rojectiles in the magazine. hould it b'e desired to change range or the rate per unit of time at which the projectiles are ejected, it is simply neces'- sary to adjust the tension of spring-34 by rotating head 38 of its set screw: Should it be desired to actuate the gun to discharge one projectile at each actuation of the piston', the

tension of the screw is adjustedfso that the valve will open at a pressure equal to or less-l than the maximum pressure generated b the .compressor at each actuation of its plston and if it is desired to shorten the range-{tension of the spring 'is' further released so that the gun barrel is m open communicationwith the compressor at any desired pressure less than the maximum.

I claim: r

l. In a pneumatic gun for use in shooting galleries and the like, the lcombination of a mechanism containing casing, an air compressor and a motor for driving 'the same contained in said casing, a gun including barrel,

etock, trigger and sights mounted on said casing, a swivel joint connection between the casing and gun, a projectlle magazine earned by the gun barrel and movable therewith, an

agitator and a motor for driving the same both contained in said magazine, said magazine operatively connected to the gun barrel, for sup lying projectiles to the gun barrel, a exibl conduit leading from the compressor extending through the casin and dischar into the bore of the barre to supply project' e ejecting air thereto and a control actuatedA b the trigger for causing both motors to ction.

2. Ina pneumatic gun of a non-explosive type, the combination of a gun barrel, means barrel, an aircompressor of the reciprocating piston type constitutingv the sole source of compressed air for discharging the projectiles, said compressor having its discharge end in fluid communication with said barrel for intermittently delivering a charge of prof jectile propelling air to the barrel, whereby at eachcompressor stroke of thecompressor piston a projectile is discharged from the gun, and the gun will lire with the rapidity of the actuation ofthe compressor and means for automatically shutting olf communication between the compressor and gun`barrel on each air intake stroke of the compressor.

, 3. In a pneumatic gun of a non-explosive tfry the combination of a gun barrel, means or feeding projectiles automatically to said barrel, an air compressor of the reciprocatmg piston type capable of generating a charge of compressed air under pressure suiiicient to discharge the projectiles from the gun barrel, said compressor havi its discharge end in fluid co unication w1tho said barrel for intermittently deliverinlna charge ofcompressed projectile prope g air to the barrel, whereby 'at each compressor stroke` of thecompressor piston a projectile isvdischarged from the gun, and the gun will fire with the rapidity of the actuation of the compressor.

4. In a pneumatic gun, the combination' with a gun barrel mounted for aiming and provided with a trigger, of an air compressor" or supplying projectile propelling air to the gun barrel, an electric motor for riving the compressor, and means forming an electric .for projectileslautomatically to said i circuit including said motor and a circuit closer controlled bysaid trigger whereby the supply of air to the gun barrel is controlled by the actuation of the trigger o f the gun.

v 5. In a v neumatic gun, the combination with a gun arrel, of means for supplying to the gun barrel air under pressure, a magazine for supplying projectiles to the gun barrel and rotary means lncludingan electric'motor for driving the same housed within the magazine for agitating the projectiles therein.

6. In a pneumatic gun, theV combination with a gun barrel, of means including an electric motor for supplying projectile propelling air to the gun barrel, a magazine for supplying projectiles to the gun barrel, meansincluding an electric motor for agitatin the projectiles in the magazine, and means ormmg an electric circuit and including both of said motors and a single manually actuated control.

7. In apneumatic gun, the combination of a gun barrel, means for feeding projectiles thereto, an air compressor, a valvemormally closing communication between the compressor and barrel, a spring tending to maintain the valve closed, said valve movable into open position when the air pressure from the compressor and acting on the valve is suili cient to overcome the closing eect of said spring.

8. In a pneumatic gun, the combination of a gun barrel, means for feeding projectiles 5 thereto, an air compressor, a valve normally closing communication between the compresser and barrel, a slpring tending to maintain the valve close said valve movable into open position when the air pressure from lo the compressor and acting on the valve is suflicient to overcome the closing effect of said spring, and means for adjusting the tension of said spring thereby to regulate the pressure of the air admitted to the gun barrel.

15 9. In a pneumatic gun, the combination of a gun barrel,'means for feeding projectiles to said barrel, a source-of compressed air leading to said barrel for expelling the projectiles therefrom and spring regulated control go means between said source and said pro'ectile feeding means for automatically regulating the projecting force of the air admitted to the barrel. y

10. In a pneumatic gun, thevcombination of z5 a gun barrel, a compressor for supplying air to the barrel to propel projectiles therefrom,

a valve normally closing communication between the compressor and barrel and responsive to a deinite pressure generated by the 80 compressor and acting on t le valve to move the same into an open position, and thus permit the air at such definite pressure to act on the projectile at the time being in the barrel.

11. In a neumatic gun, the combination of 85 a gun barre an air compressor, a short length of conduit providing a direct fluid connection between the compressor and barrel to supply projectile forcing air thereto, means for supplymg a stream of projectiles, one by one to 0 said barrel and means controlled automatically by the pressure of said air for causing said projectiles to be ejected successively from the barrel.

Signed at Atlanta in the'county of Muscoee and State of Georgia this 30th day of une A. D. 1927.

ROBERT BIGHAM SMITH. 

